Cotton harvesters often have a row unit structure with picker drums rotatable about upright axes adjacent a row-receiving area of the unit. The drum includes a plurality of upright picker bars having spindles which rotate in contact with cotton plants to remove the cotton. Corresponding spindles on the bars define generally horizontal spindle planes, with a typical drum having eighteen to twenty spindle planes. Doffers which rotate between the spindle planes in contact with the spindles to doff cotton wound on the spindles and direct the cotton towards air door structure for removal from the unit towards a basket or processor.
A conventional picker bar includes a single row of spindles spaced uniformly in the vertical direction. Each spindle includes a gear end engaged by a mating bevel gear located on an upright spindle drive shaft supported for rotation within a hollow portion of the bar. The spacing between the spindle planes and thus the density of the spindles on the picker bar is limited by the spindle support and spindle drive arrangement. Currently available drive shaft bevel gear and the spindle nut mounting arrangements prevent closer spacing of spindles. Therefore, increasing the spindle density for increased drum productivity while maintaining the reliability of the spindle, spindle bar and spindle drive has heretofore been a continuing source of difficulty.